That means there is a 50 percent chance that El Niño — warmer than normal temperatures in the Pacific Ocean near the equator — will develop by next winter. As The Baltimore Sun reports, if this happens it will be the first time El Niño rears its head since 2009.

The phenomenon is known to have broad implications for weather, including a less active hurricane season and a colder winter for the southern United States. In the Mid-Atlantic it's also caused very snowy winters.

"El Niño enhances Atlantic Ocean wind shear, which is a change in speed or direction of winds at different levels in the atmosphere. The winds tear at the structure of growing tropical systems, preventing them from organizing or strengthening."

Earlier this month, Australia's Bureau of Meteorology said all of its climate models pointed to a return of El Niño. La Niña, reports ABC Rural, is thought to have brought significant flooding to Australia. Bloomberg reports that two seasons of La Niña have "drenched parts of Asia."